(1) Field of the Invention
The present invention relates to an improved shroud for a dual inner and outer cyclonic cleaning apparatus. In particular, the present invention relates to a shroud which has a perforated section that is parallel with and purposely spaced from the inside surface of the outer cyclone or container and which allows air to pass into a frusto-conically shaped inner cyclone without plugging the inlet openings to the inner cyclone through the apparatus.
(2) Prior Art
Cyclonic vacuum cleaning apparatus are shown in my U.S. Pat. Nos. 4,573,236; 4,593,429; 4,571,772; 4,643,748; 4,826,515; 4,853,011 and 4,853,008. My U.S. Pat. No. 4,853,008 describes a dual cyclonic cleaning apparatus wherein a combined disc and shroud unit is mounted on the outside of the inner cyclone in order to retain dirt in an outer cyclonic cleaner. The shroud has a perforated lower section adjacent to and above the disc which is parallel to the conical outside surface of the cyclone. The perforated section acts as an air inlet to the inner cyclone while the disc keeps large dirt particles and fibrous matter in the outer cyclone. The combined disc and shroud work well; however, there was a need for an improved design which would not allow the shroud perforations to be filled with dirt before the outer cyclone was full of separated dirt.